Tuberculosis And Antitubercular Drugs Flashcards
What is tuberculosis?
Which is the most common form?
Tuberculosis: medical diagnosis of any infection caused by a bacterial species called mycobacterium. Caused either by mycobacterium tuberculosis (MTB —> most common) and M. bovis
Most common: mycobacterium tuberculosis: need large supply of oxygen to grow and flourish (aerobic) —> most commonly found in lungs
What are some signs and symptoms of TB?
- SOB
- coughing up blood
- cough lasting more than 2 weeks
- weight loss
- chest pain
- weakness and datigue
- loss of appetite
- fever
- night sweating
- chills
- sputum
What are some TB testing tests?
- PTB test (to detect TB —> if positive then X ray)
- X-ray (to identify presence of nofules if yes sputum test done)
- Sputum culture test (med regime might be changed depending on results)
What is the antituberculin treatment intensive vs continuation?
Intensive:
- combination of meds rapidly destroy TB bacilli and improve conditions
- reduces disease transmission
- tx of 2months take 5x per week
- main meds given together to prevent drug resistance : isoniazid, rifampin, pyrazinamide and ethambutol
Continuation:
- lenght of tx varies
- based on risk of relapse
- given daily or intermittently 3days a week
- consists of use of 2 drugs
What is the Classification of the TB meds?
Name the prototypes meds for tx of TB.
Classification: aminoglycoside antibiotics
Prototype meds:
- INH (isoniazid-isotamine)
- Rifampin
- Ethambutol
- streptomycin
What is the mechanism of action and the indications for aminoglycoside antibiotic therapy for TB?
Mechanism of action:
- inhibit cell wall synthesis
- act on MTB inhibiting protein synthesis
- reduce symptoms and infectiousness of pt
Indication: TB infectiond (pulmonary and extra pulmonary)
What are some contraindications and interactions with aminoglycosides antibiotics for TB? ( isoniazid and streptomycin)
Contraindications:
- severe drug allergies
- major kidney/liver dysfunction
- chronic alcohol use
Interactions:
- Isoniazid: cause false positive urine test glucose reading
- Elevate levels of liver enzyme
What are some drug interactions with INH (isoniazid- isotamine)?
- Antacid: reduce absorption
- rifampin: additive effect = increase risk of CNS and hepatotoxicity
- phenytoin and carbamazepine: decrease metabolism so increase effect of these meds
What are some AE with INH (isoniazid-isotamine)? (TB meds)
And what is the contraindication?
- peripheral neuropathy
- hepatotoxicity
- pyridoxine (vitamin b6) deficiency
- optic neuritis
- visual disturbances
- hyperglycemia
Contraindication:
Acute liver disease
What is the indication for INH (isoniazid-isotamine)?
And how does it work?
Indication: used in pregnant women with TB
Works by disrupting cell wall synthesis (bactericidal)
What is the specific AE of rifampin?
And name other AE as well.
Specific: discoloration of urina, tears, sweat, sputum, etc.. (may be red, orange, brown, )
- hematological disorders
- hepatitis
What are some drug interactions with Rifampin?
Increased metabolism so decreased therapeutic effect with:
- beta blockers
- benzodiazepines
- cyclosporine
- oral anticoagulant
- oral antihyperglycemics
- oral contraceptives
- phenytoin
- quinidine sulphate
- sirolimus
- theophylline
What are some indications for Rifampin?
Forms available.
- used in combination with other antitubercular aminoglycoside antibiotics for TB txs
- used in preventative therapy
- safe during pregnancy
Available PO
What are the different mechanism of action for each antitubercular drug (aminoglycoside antibiotics)?
- Rifampin: inhibits RNA and DNA synthesis —> inhibits protein synthesis
- streptomycin: interferes with normal protein synthesis—> inhibits protein synthesis
- isoniazid: inhibits synthesis of the cell wall
- ethambutol: affects lipid synthesis ehich inhibits protein synthesis
Which antitubercular drugs (3) are safe during pregnancy?
- isoniazid (INH)
- rifampin
- ethambutol